Apparatus for manufacture of high melting point bitumen



Jan. 2, 1945. J. w. PACKlE ET AL 3 5 APPARATUS FOR MANUFACTURE OF HIGHMELTING POINT BITUMEN Filed Sept. 5, 1942 VA cuuM Patented Jan. 2, 1945APPARATUS FOR MANUFACTURE OF HIGH 9 1 MELTING POINT BITUIHEN John W.Packie, Green Village, and Raymond E.

Bittner, Phillipsburg, N. J assignors to Stand- Company, a corporationard Oil Development of Delaware Application September 5, 1942, SerialNo. 457,468 1 Claim. (01. 196-114) This invention relates to improvementin equipment for separating liquid and vapors at high temperatures andhigh vacuum and particularly for separating bitumen of high meltingpoints from petroleum hydrocarbon oils Without any substantial crackingof the products.

Bitumen having softening points above 200 F. are very difficult toseparate from the oil in which they are found. There are certain bitumenoils obtained in Venezuela that contain bitumen having softening pointsranging from 200 to. 350 F.

It is necessary to separate these bituminous substances, from the oilwithout any substantial cracking, as cracking greatly augments thequantity of vapors to be handled by the evacuating equipment and makesthe maintenance of a low absolute pressure in the separating zonevirtually impossible.

An object of this invention is to effect a separa tion by vacuumdistillation of the bituminous sub stances having softening points above200 F. from the oil fraction in which they are normally found.

g In order to obtain high melting point pitch bottoms from relativelyheavy charge stocks, the low boiling fractions must be separated fromthe bitumen at relatively high temperatures and low absolute pressures.The vapor fractions separ ated from the bitumen in the separatingchamber contain some high boiling fractions and also contain someentrain'ed bitumen. These vapors must be scrubbed with liquid to recoverthe entrained bitumen and to improve the color and carbon content of therecovered-relatively low boiling oil fractions. However, the vaporscannot be cooled substantially as this would result in condensation ofsome of the low boiling material which, if permitted to combine with theliquid bitumen in the base of the separating chamber, would result inthe dilution of this product with a consequent reduction in the meltingpoint. Accordingly, with normal separator tower construction in whichthe refluxing liquid introduced in the top of the tower flows down thetower and if not revaporized will finally be admixed with the liquidfractions in the base of the tower, the

quantity of refluxing liquid must be small in relation to the quantityof overhead vapors. With this small quantity of liquid passing over theseparating devices in the tower, a; considerable the separating zone.This is especially true if bubble cap trays are used in the tower. Theobject of this invention is to eliminate these diffi culties. This isaccomplished by using an internal construction of baflle plates andother sep- [arating devices which do not result in restricted "passagesfor the ascending vapors. In addition, I the deposition of coke on thebaflies is prevented by maintaining a high rate of liquid flow over thesurfaces and a low hold-up time of liquid on the surfaces. g

The various features and novelties of the invention will befullyunderstood on reading the following description with. reference tothe accompanying drawing. q.

A Venezuelan crude containing the highsoftening point asphalt is firstsubjected to distillation and/or viscosity breaking and distillation toseparate the oil fractions boiling at low temperatures; that is, boilingbelow 500 F. to 600 F. The residual oil is then passed to a vacuum towerI by means of pipes 2 and 3, after being heated I while confined in anarrow stream in a furnace. This residual oil is introduced into thelower part of vacuum tower I beneath plate 4 where a temperature ofabout 775 F. and a pressure of mm. is maintained. superheated steam maybe introduced intothe residual oil as it is being passed through theheating coil. The bottom section'of the tower is provided with a seriesof baiiie plates and also maintained at the desired temperature by meansof superheated steam introduced through pipe 6. The volatile fractionsof the residual oil pass upwardly through the opening I provided withdownwardly extending flange baffles in plate 4 and opening 9 in drawofipan 8.

Opening 9 is provided with upwardly extending flange baflles. Pan 8 isslanted and any liquid oil fraction entering pan 8 is removed by means.of pipe I0 and passed to heavy recirculating drum II where by means ofpipe I2 and pump I3 it is passed to pipes and I5 to the vacuum tower Iabove drawoif pan 8. Any volatile fractions separated in heavyrecirculating drum II may be returned to the vacuum tower I abovedrawofi plan 8 by means of pipe I6. A series of baflle plates isprovided in vacuum tower I above pan 8 and beneath an upper pan I'I. Thecondensate in pan I1 is removed through pipe I9, passed through lightrecirculating pumps 20 and returned to the upper part of the vacuumtower I by means of pipe ZI. The temperature maintained in the upperpart of vacuum tower I is together with the entrained bitumen removedfrom the vapors are collected in drum II. This heavy high viscositymaterial may be removed from the system through line 3| or they may berecycled back through the heating coil and into the separating chamberthrough line 32. .In the latter case, this recycled material isseparated into a bitumen fraction and an oil fraction, as is theoriginal charge. This results in maximum yield of the desired bitumenfrom the feed stock. Trays 22 and 23 are also provided in the iupperpart of the vacuum tower I. These are preferably perforated trays sothat the liquid sprays down throughthe vapor space, thereby scrubbingthe ascending vapors. this tower by means of vapor lines 24, 25, 26, and21. Cooling in the tower is accomplished by returning to tray 22 some ofthe condensed overhead vapors. By maintaining pressures not over '70 mm.and temperatures ranging from 700 to 775 F;, a good separation of thebituminous material without substantialcracking is obtained.

'Theffinished productof bitumen is removed from the bottom section ofvacuum tower Iby means of pipe 28' and after passing through 'a pitchsurge drum 29 is passed to storage. The 'vapors in pitch surge drum 29are removed by means of pipe '30.

We claim:

An evaporator for low vacuum flashing of hituminous oil 'toproduce highmelting point bitumen, comprising a shell; means 'for introducing theoil into the bottom of the shell 'at a tempera ture of about 750 F.,means formaintaining a Vapors are removed from pressure within the shellof about'ZO millimeters, a lower wash system for vapors from the bitumenmaterial flowing upwardly through the shell and comprising a slopingannular tray with an upwardly extending flange on its inner periphery, aconduit leading from the bottom of the tray through the shell to aseparator and returning to a ba'file above the trayfor circulation ofwash liquid, an annular plate with depending flange around its innerperiphery between the inlet for loilland the tray, anrupper wash systemcomprising a horizontal annular tray with upwardly extend- .ing flangeon its inner periphery, a conduit leading from the tray through theshell and returning to :a baffle above the tray to circulate Wash liquidwhereby the upwardly ascending vapors are.

washed to remove bituminous material, conduits leading from the top ofthe shell to withdraw the washed vapors, a chamber of reduced diameterdepending from the bottom of the shell and provided with-baffles overwhich the stripped bitumen flows, a steam inlet at the bottom of thechamber for maintaining the temperature within the chamber and for steamwashing the stripped bituminous material descending through the chamber,and a conduit extending from the bottom of the chamber for leading thestripped-bituminous material from the shell -'whereby separation of thebituminous material from the oil "is effected without substantial'cracking and the passages through the shell are maintained :openv JOHNw. PAoKr-E. RAYMOND 131mm;

